This application claims the priority of German Application No. 196 24 046.8 filed in Germany on Jun. 17, 1996, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a process and an arrangement for indicating the braking intensity or the deceleration of a vehicle to one following the vehicle.
For warning traffic participants who are following a leading vehicle, the application of the brakes of the leading vehicle is conventionally indicated with two or three brake lights located on the rear exterior of the vehicle. In road traffic, a driver of a vehicle following the leading vehicle is momentarily informed only that the driver of the leading vehicle is operating the brake pedal. The brake light signal provides no direct information to the following driver concerning the actual intensity of the braking or the deceleration of the leading vehicle. On the contrary, the following driver must observe and assess additional visual information to determine the deceleration of the leading vehicle, for example, by recognizing how fast the relative gap between the two vehicles is changing. Depending on how well the following driver detects and assesses this secondary visual information, the following driver must attempt to adapt the speed and the gap more or less to the vehicle driving ahead.
It is important to better inform the following driver concerning the braking operations of the leading vehicle so that the following driver can assess this situation better and faster. On the whole, this will help to reduce the number of collisions.
The human detection of the braking operation of a vehicle driving ahead is particularly difficult under conditions of poor visibility, for example, in fog, rain or at night. In such conditions, it is difficult or even impossible to distinguish the peripheral visual information. The result is a belated awareness and a longer required observation time for recognizing the situation. This often leads to a braking reaction which is not adapted to the situation, for example, to an insufficient braking deceleration, an overreaction, or a belated braking operation.
It has been discussed for some time that the one-step signalling of a braking operation (i.e., braking vs. not braking) does not contain sufficient information for the driver who is following a leading vehicle.
For example, German Patent Document DE-OS 23 61 356 discloses a switching operation for operating the brake lights of a vehicle. It is then described that, particularly under conditions of poor visibility, the secondary "hints" when a vehicle driving ahead is braked cannot be detected optimally and in time. For this purpose, indicating conditions are provided which are adapted to a respective braking condition, specifically a brief switching-on of a brake light in a first condition; a continuous operation of the brake light in a second condition; and a pulsed brief switching-off of the brake light in a third condition.
German Patent Documents DE 43 05 186 C2, DE 34 31 898 A1, DE 37 02 718 A1 as well as DE 38 11 339 A1 and DE 40 20 464 A1 also relate to blinker signals.
German Patent Documents DE 43 05 186 C2 and DE 40 03 313 A1 also provide additional information concerning the braking intensity by means of an enlargement of the lighted surface of the respective brake light.
Finally, in German Patent Document DE 31 19 386 A1, variables are determined of which at least one depends on the operation of the brake pedal. On the basis of the variable which corresponds to the deceleration of the vehicle driving ahead, the light intensity of the brake lights is determined.
In the case of all above-mentioned processes or arrangements it is a disadvantage that the visual information, particularly the flashing information, assigned to a certain braking action must usually first be learned in order to be able to assign it to the corresponding braking action. The information learned by such a learning operation must, at least in an initial phase, be called up by way of a conscious mental step during a later application. Such a consciously made mental step more or less requires time for the recognition of the meaning of the perceived visual signals. Particularly in critical situations, this time is extremely scarce so that it should be kept as brief as possible.
It is an object of the present invention to further develop a process and an arrangement of the initially mentioned type so that detailed deceleration and braking information can be detected and assigned within a very brief time period without the requirement of a learning process.
These and other objects have been achieved according to the present invention by providing a process for indicating a braking intensity of a vehicle, comprising: generating a signal which corresponds to a deceleration of the vehicle; displaying a lighted area on a display device including at least one brake light; and controlling the lighted area based upon said signal to vary at least one of a size, a position, a light intensity, and a color of said lighted area to correspond to a level of the deceleration.
These and other objects have also been achieved according to the present invention by providing an arrangement for implementing the process for indicating the braking intensity or the deceleration in the case of a vehicle, having a signal generating device which generates a signal corresponding to a deceleration, a display device which has at least two brake lights which indicate a braking information assigned to the respective signal, and a control device which controls the display device on the basis of the signal provided by the signal generating device, wherein the control device and the display device are constructed and coordinated with one another so as to control the lighted area based upon said signal to vary at least one of a size, a position, a light intensity, and a color of said lighted area to correspond to a level of the deceleration.
The essence of the present invention is therefore to take into account stimulus factors, of already known information, which occur during a deceleration operation and are essentially perceived and processed by the subconscious. When the leading vehicle which so far has moved along at the same speed as the following vehicle is braked, a number of secondary effects occur which are indirectly generated by the deceleration and are directly generated by the relative closing distance between the two vehicles.
When a braking operation of the leading vehicle is initiated and the relative distance between two vehicles is therefore reduced, the driver of the following vehicle perceives a change of the light intensity of the brake lights. Furthermore, in the case of an approach between two vehicles, because of the change of the visual observation angle, the following driver will perceive a size change of the luminous surfaces of the brake lights as well as of a position change of the luminous surfaces.
In the case of a more intensive braking of a vehicle driving ahead, there will also be a "braking dive" which results in a lifting of the brake lights. From experience, a vehicle operator will also be familiar with this information. He does not have to learn the interpretation of all above-mentioned visual stimuli and information. Such visual stimuli and information is exercised and absorbed such that, without any learning process, it can be translated directly and essentially from the subconscious. By means of the above-mentioned measures, so-called stimulus factors which are represented as visual information by means of the brake lights are optimally taken into account. The normally occurring secondary effects during a braking operation are used in a targeted manner for coding the braking intensity.
In one preferred embodiment, the main illumination points of the lighted surface assigned to one brake light respectively experience a position change corresponding to the intensity of the deceleration. The main illumination point is that point of a luminous surface which is surrounded by the lighted surface in the same manner, thus with respect to the point of concentration.
Such a position change results from the fact that the main illumination points of the lighted surfaces of two brake lights of a vehicle arranged side-by-side appear to move toward the outside relative to one another as one is approaching the vehicle. Therefore, this embodiment utilizes the effect which is generated by the approaching vehicle in the case of which the brake lights seem to move apart because of a change of the observation angle.
According to another preferred embodiment, the main illumination points of the brake lights are moved upward with an increased deceleration, which utilizes the effect of the braking dive of a vehicle. Depending on the intensity of the deceleration, the vehicle operator who is following therefore receives an intensified information with respect to the intensity with which the vehicle driving ahead is decelerated.
According to another preferred embodiment, the illuminated surfaces of the brake lights are enlarged to intensify the following driver's perception of approaching the leading vehicle, possibly in combination with one of the previously mentioned processes.
The increase of the brightness of the lighted surface of a brake light has a similar effect. A brighter light can naturally be perceived to be the result of a more intensive braking, without the requirement of learning this relationship previously.
According to another preferred embodiment, at least one additional brake light is arranged which will light up only starting at a specific deceleration intensity.
The attention of vehicle operators who are following will increasingly be drawn if the change of the indication, such as the position change, the intensity change or the size change of the lighting-up surface, takes place in discrete steps. A "jump" of the lighting-up surface will increasingly signal that the deceleration is now in another, possibly more dangerous range. A two-step or three-step indication is preferably used in this case.
In order to be able to better assign the indication, according to another advantageous embodiment, when the braking is carried out at a certain deceleration value, before the visual braking information is indicated which corresponds to this deceleration value, there will be a successive passing through all braking indication steps which are connected in front and correspond to a lower deceleration. As the result of the successive passing through of the preceding braking indication information, the operator of a vehicle which is following can better estimate the deceleration because he or she knows that the indication must not be assigned to a braking in a lower range but to a range which is above it in steps. This eliminates a confusion of the individual indication steps.
According to further advantageous embodiments, for generating the signal corresponding to the deceleration, the brake pedal operation (for example, the brake pedal force or the speed of the pedal operation) and/or the braking pressure in a brake circuit and/or the operation of an antilock system and/or the coefficient of friction between the road and the wheels and/or the operation of the gas pedal will be analyzed. Naturally, it is also possible to analyze additional information which provides information on an acceleration or deceleration of the vehicle.